Atopic subjects seem to be predisposed towards the disease, however some non-atopic subjects are also affected.

IgE-dependent mechanism.

The allergen is a low molecular weight protein.

ConditionsContamination of work place and surrounding areas during processing. When castor oil cakes are used as "natural" fertilisers, a number of different professions may be affected including deliverymen, retailers, wholesalers etc.

The volatile organic components of rapeseed can be irritative and/or allergenic. These rapeseed oilcake/cattle-cakes are used in the feeding of livestock. Cases of occupational asthma have recently been reported in animal breeders, demonstrating that moderate exposure, and even occasional exposure can give rise to true sensitisations.

SymptomsViolent asthmatic attacks, epidemic, symptoms cease after contact with the causative agent. Attacks may be immediate or delayed. In the case of asthma caused by ambrette (Hibiscus Abel.) working with oilseed and powdered seeds also causes eczema.

Bronchial provocation tests (in hospital) must be preceded and followed by a measure of bronchial hyperreactivity. The threshold for bronchial hyperreactivity is lowered following the bronchial provocation test. Eosinophil numbers are increased in induced sputum in cases of asthma induced by these allergens.